What Makes a Projector? (Part 1)

Projectors have come a long way over the years.  At first they used film to feed through a mechanical shutter with the 2 large reels holding the film. Now they have become stand alone display devices.  More similar to a TV screen than a slide projector.

What makes them what they are today? There are essentially two answers to that question.  One is LCD technology and the other is DLP technology.  They both use replaceable lamps, but how they use those lamps to create the image is what sets them apart.
This begins a short series on Projector display technology.  This post we will cover DLP Projectors.
DLP is an acronym for Digital Light Processing. Invented in 1987 by Larry Hornbeck of Texas Instruments the digital mirrored device chip(DMD).

The first video projector to use this technology was built by Digital Projection in 1997.  Both Digital Projection and Texas Instruments won an Emmy Award for the use of DLP technology.

A DMD chip(pictured above) is made up of microscopic mirrors arranged in an array on the chip surface.  The mirrors are controlled via small electrostatic pulses to adjust their angle.  The angle causes them to either reflect the light out the lens onto the screen or away from the lens to create black or lack of light.  Each mirror is made up a microscopic yoke, torsion spring, and the electrostatic pads that affect the memory cells that set the position.

The diagram to the right shows the construction of each pixel.  Depending on the resolutions the amount of pixels changes. For instance an 800 x 600 DMD has (800*600 pixels= 480,000) pixels or mirrors that are controlled.  However some chips use a method of oscillating the mirrors to have them act double duty, halving the amount of mirror elements needed in a DMD chip.  

DLP Chips are monochrome or single colored. They can only turn light on and off and adjust its brightness. It cannot color the light.  This is where the next most important device of a DLP projector comes into play.
The Color wheel is a glass wheel made up of multiple segments all with a different color glass light filter.  On average they use 4 segments: red, blue, green and clear. Some models have multiples of the same color.  Others use 6 segments colors red, purple, blue, light blue, green and yellow.  The projector syncs the rotation of the color wheel and the color needs of the DMD while the image is being projected. DLP uses optical persistence to “fool” our eyes into seeing a mix of colors when in reality the projector is only projecting one color at a time for a fraction of a second.  If you blink your eyes quickly while looking at the DLP projected image, you can see the colors by themselves.
These 2 devices more than any other set the DLP projector apart from LCD.  Other differences are in the electronics.  There are a whole set of electronics that only are there to support and control the DMD chip.  These electronics are not as physically obvious but are no less important. These chips are for driving the electrostatic control signals to the DMD, as well as the video processing chips that prepare the signal to the DMD controller.  There is a motor control chip that keeps the color wheel in sync so that why the DMD is projecting the red portion of the image, the red color wheel segment is in position.  These all work together to ensure a pleasant and vibrant image.  
The main benefit of DLP over LCD(at the time) was the contrast ratio. Contrast ratio is the difference between a full white and full black image. When using a lamp to create an image there is almost no chance of having true black as black is the absence of light.  Turning off the lamp for the black portions of the picture is not practical.  Rather the pixels that require black merely point their light away from the main lens creating black on the screen.  Since the mirrors are only pointing away, there is some minor light leakage so the “blacks” are not as black as they could be.  The higher the ratio, the darker the blacks and brighter the white bits of the image will be. This was more of an issue with DLP first came to market as LCD had abysmal contrast.  These days they are pretty much the same contrast ratio-wise.
The last and most obvious difference is the lamp used in DLP.  Both DLP and LCD use Short ARC Mercury vapor lamps but only DLP uses this particular arrangement.
DLP Lamps commonly use a non-optical lens. Meaning there is no focusing or change in direction of the light beam.  Rather they have lenses inside the optics that do any light adjustment needed.  The lamps do have a special coating on the lens(ND filter lens). That coating prevents UV(ultraviolet) and IR(infrared) light from being injected into the light path.

DLP Lamp with UV/IR coating

LCD LampThese can harm your eyes and the optics due to heat and radiation.  This coating is a big reason why we do not recommend replacing only the bare bulb. If that coating fails or fails just a little it can cause your color wheel problems and possibly even melt some of the lenses.

Here is a picture of the internals from a Polyvision PJ905 that uses a 2002031-00 Lamp that has the proper coating.

PJ905 Internal diagram of DLP projector.

This about sums up the DLP video projector.  They are a reliable and well proven piece of technology.  Pureland Supply takes a lot of pride in our lamps and we make sure every lamp that is used in a DLP projector(as well as LCD) is configured correctly to perform as well as possible for you.  Check our selection of lamps here. 
Stay tuned for next week when we discuss LCD projectors. If you have any questions please do not hesitate to contact us at 1-800-664-6671 or Sales@purelandsupply.com
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Tips to Identify Your Projector Lamp

There are thousands of different projector lamps. If you don’t believe me, look at our Website in the Epson Section, as an example.  Epson alone has around 100 different lamps. Last count we had about 3100 unique items with close to 20,000 associated Model numbers. That is a lot of info.

Occasionally we get a call or email asking for a lamp but the customer is not sure of the brand or model.  When you are not the one replacing the lamp and you have to buy the lamp, it can be stressful and difficult without that info.

There are a few tips that I can share that will help. 

First and foremost ask your tech / installer for as much info as possible.  The ideal info is the model number off the projector.  All projectors have a data plate.  Its the sticker or metal plate that has all of the units pertinent info such as the model, serial number, power rating and any certifications.  That plate is usually located on the underside of a projector.  The underside if its sitting on a table. When that is the case, getting that info is easy.

Now say the projector is mounted 30 feet in the air, and you have to rent a lift to get the old lamp out?

The data plate might be blocked by the mount.  It may also have faded from years of sunlight on the sticker.  What can you do?

We have a lot of info at our fingertips.  While we prefer the proper info such as the model number or lamp number, we can usually identify a lamp pretty precisely.

What I am going to teach you is a last ditch option.  After you have exhausted all other options see how this goes.

I’ll start with the useless info.  All housings have numbers on them.  Sometimes they mean things.  Many times they don’t.

Most lamps will list the type of plastic they are made from. This is one of two types.  PPS and LCP.

PPS is Polyphenylene Sulfide. Its a higher temp thermoplastic that usually has some glass fiber re-enforcing.  Commonly listed as PPS-GF40 (Polyphenylene Sulfide Glass fiber 40%).  You can visually tell by the look of the plastic.  It will be glossy and hard.

The other kind of plastic used is LCP (liquid Crystal Polymer).  It is no better or worse.  I can only speculate on why one would be used over another as they compare almost the same with only negligible differences.

If you see PPS-GF40/GF30 or LCP-GF40, you can ignore those numbers.  They are only useful to the plastic recycling center.

There may also be a 2 digit number. That is usually a mold ID.  When the lamp housing was molded it was done so in a mold that had a number in it. That is for quality tracking.  Also not much help for finding your mystery lamp.

There may be other random letters and numbers. Most of them will be useless.

Here is what you WANT to look for.

Flip the lamp over and look at the back of your bulb.  Most lamps will have markings on the bulb unless its a cheap knock off.  You know how I feel about those.

That bulb will have some numbers.  Those will be helpful. They may not ID the lamp entirely but it will narrow it down immensely.

Refer to this chart:

Ushio:  Look for NSHxxxY(x= numbers, y= letter suffix)  or NSHAxxxY.  NSH refers to a DC (direct current bulb) and should have at least one wire physically attached. NSHA is for AC(alternating current bulb) and will have 2-3 terminals that can have a connector attached via screws. Many Ushio bulbs are purpose made for a specific manufacturer.  For instance, NSH200EDC is a 200W DC lamp made for Eiki with 3 terminals instead of 2.

Philips:  The first number on the sticker is the part number.  In this image the 636 is the part #.  The 90 indicates that this is an aftermarket bulb for Original Inside lamps.
UHP Philips Bulb
We can match that info to a handful of lamps.

Osram:  There will be a sticker on the reflector or text on the read of the ceramic. You are looking for the “PVIP” data.  It will say P-VIP xxx(x= wattage) then the arc gap(1.0 or 0.9 or 0.8) which is the spacing in millimeters inside the arc-tube.  Then the reflector size which will be a P (for parabolic) or E( for elliptical) and a number.

Phoenix: This is the most difficult but fortunately its also rare.  There will be a short number such as SHPxx on an OEM.  The aftermarket lamps are harder.  They use a 3 character listing such as GX4 or SX5.  They have the wires permanently attached and usually are in older lamps.  Even so, if we know you need a lamp with a Phoenix bulb it will still eliminate a lot of variables.

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Knowing the brand of the projector will then get us even closer if not to the exact model.

Lastly take a picture for us.  We look at lamps all day long. Whether in our Quality Control Department or by our warehouse staff, some of us can ID a lamp by just seeing it.

Set the lamp on a nice clear background.  White table or solid lighter colored surface.  Put a piece of paper under it if you aren’t sure.  Then take a picture looking straight down. Make sure to get the connector in the shot.  Then take another from the bottom with the lamp flipped over.

Refer to the image below. The first two pictures show a POA-LMP94 from a PLV-Z4 /PLV-Z5.  The third picture is the same lamp but while its a ‘nice’ picture, its not recognizable as easily.

Ideally of course, get the model number.  Even if you have what you believe is the proper Lamp ID , use the Model number.  It is the best way to guarantee you are sent exactly what you need and nothing less.

We can ID most lamps the same day as our staff is highly trained and well versed in finding the lamp you need. Contact us Monday through Friday 9am to 5pm via phone or Chat or anytime at Sales@Purelandsupply.com and we will reply the following business day.

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Congratulations to the Philadelphia Eagles..and your Projector!

Congratulations to the 2018 Super Bowl winners, the Philadelphia Eagles!

Being a company based out of the Philadelphia area, we have a lot of Eagles fans who work here.

While New England played hard, it was nice to see the Eagles play a little harder.  The same can be said for your video projector.  Each projector is an engineering marvel that balances cost with function.

Think of your lamp like the Quarterback.  The lamps job is to pass light through the optics to the end-zone/screen.  Your lamp is constantly at odds with elements looking to make it fail.

Heat and dust are working hard to chip away at your lamp life, but the supporting members of your projector team work to protect it. The cooling fans are the Lamp’s Guards, while the filter is the Lamp’s Fullback. The rest of the team has its own purposes to ensure long life and clear pictures of your projector.

With the Football Season over for now, its a great time to start planning for next season.  4K projectors are becoming more reasonably priced and their lamps are some of the brightest to be made yet for the price range.

You can use the next few months to decide the best course of action to install your new projector or put your old projector into “pre season training” by making sure its been cleaned and replacing your lamp if its nearing the end of its life or starting to look dim. Its better to change your lamp before it fails.  You can save the old one as a back up and return the unit to its original brightness.

If you are looking to upgrade a good example is the BenQ HT2550 projector.

BenQ HT2550

This is a true 4K (3840×2160)model rather than an enhanced 1080p (1920 x 1080)Projector like the Home Cinema 4000 .  The BenQ HT2550 retails for around $1,500.  Unlike the Sim2 Crystal 4 UHD which is 10x the price.

The BenQ projector has almost the same specs as the Sim2.  While Sim2 is a fantastic brand, it is not the most affordable and is not an entry level of average consumer level unit.

Sim2

Pureland Supply offers a lamp for each of these unit.  You can search for this BenQ or your model BenQ via our Manufacturers page.  It lists every model and lamp for you to browse through, or you can use the search function to find your specific model or lamp number.

Of course if you are unable to find the model you are looking for or have any questions at all, our team at PurelandSupply is ready to help you with any of your projector lamp questions.

Give us a chance to support your projector for the rest of 2018. Contact us at 1-800-664-6671 via Phone or Online Chat Monday-Friday 9am to 5pm Est. We can also be contacted via email 24/7 at Sales@purelandsupply.com.  

Logo image for Pureland Supply

GO EAGLES!!

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High School students can apply now for new Scholarship at Pureland Supply

Are you getting ready to head to an accredited Vocational School, Trade School or Community College this fall?

Here is an excerpt from our website describing the scholarship:

Pureland Supply sells high quality replacement projector lamps to various Universities, Schools, and Government entities.  We understand the importance of skilled trades in our society and appreciate those who learn and perform specific occupational trades. 

The $1000.00 Pureland Supply Scholarship
 is open for students who have been accepted to an accredited Community College, Vocational College, Technical School, or Trade School.  Recipients are chosen on their ability to describe how their chosen trade or field plays an important role in today’s world and how the student expects to play a part in the future of their trade or field.

If you plan on attending a school that fits into the above description, you should click on THIS LINK to head over to our scholarship page.  Its also well recommended to visit our Facebook page for updates and of course the usual specials or coupons we offer there. 

Pureland Supply plays a large roll in the technical fields of AV Presentation, Simulators of all kinds and all of the other areas Projector lamps are used in aside from the usual home theater use.  

The fact that we are able to give back to help others move ahead in that area means a lot to this blog writer personally.   For years the trades were being forgotten. College is a wonderful option for a lot of people, but there are a lot of professions that College is not the answer for.  As this article states, its time to show people that Trades are a well respected and well paying option.


You can download the application HERE or from the Scholarship page itself. 


We will announce the recipient of the Scholarship via our Facebook page July 1, 2018.


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